The present invention relates to a tool holding device configured for attachment to a drive spindle of a machine or power tool and used for holding tool bits that are worked by the machine or power tool, and more particularly to a quick-change chuck device that permits change-out of tool bits without the necessity of applying an external tool or wrench to the chuck.
Any collet or chuck device utilized for holding a tool bit to a drive spindle of a machine tool, such as a router, must lock the bit both axially and radially with respect to the drive spindle. In other words, the chuck must prevent the tool bit from rotating relative to the drive spindle and from moving axially toward or away from the drive spindle. This concern is particularly important with high speed machine tools, such as routers, laminate trimmers, dry wall cutters, etc., both for accuracy and safety considerations.
With conventional systems, one relatively simple means for rotationally securing the tool bit consists of defining a hexagonal or other multi-sided profile on the end of the tool bit which fits into a corresponding multi-sided recess formed in the chuck device. With this conventional mechanism, the operator typically needs to use at least one wrench and a spindle lock, or two wrenches, in order to change the tool bit.
With another known device, collet chucks utilize a compressible collet for axially and rotationally holding the tool bit. Collet chucks are useful in that they do not depend on a multi-sided configuration in the tool bit for holding the tool. Thus, any manner of power bits or tool bits having essentially round shank portions may be held by a collet chuck device. However, collet chuck devices do not have the quick-change or quick release capabilities that are desired in many applications.
It is highly desirable for portable tools, such as routers or laminate trimmers, to utilize a quick release chuck device for relatively quick and easy change out of tool bits. However, with the conventional quick release devices, the tool shank portions must be multi-sided to fit within corresponding bores defined in the quick-change chuck devices. It would be desirable in the art to have a quick-change chuck device which can be utilized with any manner of tool bit, including tools bits that have essentially round tool shanks, for increasing the versatility and ease of operation of machine tools utilizing such chuck devices.
Also, with many types of conventional chucks, it is necessary to hold the tool bit at a desired height relative to the chuck while tightening or otherwise actuating the chuck until the tool bit is securely held by the chuck. If the tool bit is not held during the tightening operation, it will fall out of the chuck or into the chuck up to the working surface of the too bit, depending on the orientation of the power tool. This can be a difficult exercise, particularly when space in the area of the chuck and tool bit is relatively limited, for example as with routers wherein the space in the area of the router guide and chuck is very limited. It is particularly awkward in this situation when the operator must use both hands to change out the tool bit. One hand must hold the tool bit to ensure that it remains at a proper height, while the other hand is used to actuate the chuck. It may also be necessary for the operator to physically grasp the tool bit on relatively sharp cutting edges thereof, which is an obvious undesired situation.
An additional problem with many conventional types of chucks is that dirt, debris, etc., tends to migrate into the body of the chuck and eventually degrades performance of the chuck or causes the chuck to fail. This is particularly true in many routing applications wherein the chuck operates in very close proximity to the router bit.
The present invention also relates to a chuck device incorporating a feature to retain a tool bit or shank inserted into the chuck at a specific height regardless of the actuating position of the chuck. The tool bit retaining feature may also act as a seal for the chuck to keep dirt, debris, etc., from entering into the body of the chuck.